Dispersed fine opacities fill most of the vitreous cavity. A membraneous structure crosses this cavity and inserts into the optic disc (the dark empty appearing area of the orbital pattern near the bottom end of the B-scan corresponds with the optic nerve).

Is this membraneous structure a detached retina or the posterior surface of a detached vitreous?

The answer comes easy with the A-scan.

Several low to medium high spikes interrupt the baseline of the vitreous cavity centrally. These spikes indicate dense vitreous hemorrhage.

A chain of very low spikes is overlying the right half of the vitreous baseline. These low spikes represent very dense subvitreal hemorrhage (hemorrhage underneath the detached vitreous).

The single medium high spike separating the vitreous from the subvitreal opacities corresponds with the posterior surface of the detached vitreous. This spike corresponds with the long echo line seen in the B-scan. This is not retinal detachment which would produce a 100% high spike.

Notice the difference in reflectivity between the vitreous hemorrhage (higher spikes) and the subvitreal hemorrhage which inspite of greater density reflects weaker echoes.